Explain what happens to the state space, the possible behaviours and the reachable state space when two automata are coupled. [3 marks] (b) The Banker's Algorithm can be viewed as a predicate over shared state. What state does it operate over and does this include the program counter of the participating threads? When does it return true or false? [6 marks] (c) What is the difference between strict and non-strict isolation in a transaction processing system? What do both approaches ensure? Which can lead to a transaction abort being forced by the system and why? [3 marks] (d) "Increment and decrement operations are freely commutable" ? what two assumptions are required for this statement to hold? Is it true that the effects of transactions containing increment and decrement operations are always serialisable? [3 marks] (e) Customers interact with a transaction processing system over a web interface but confirmations are also sent by email, such as 'please collect from your local branch'. Should the email message be generated before, during, or after the process of committing the order transaction? What are the advantages and disadvantages of different approaches? Fully justify at least two design decisions in terms of system complexity and durability over a system crash. [5 marks]

11:22 SEHH1034-Additional Assignment-... Section A (60 marks) Answer any FOUR out of the FIVE questions in this section in the answer sheets provided. Each question carries 15 marks. If you answer more than four questions, only the first four attempted questions will be marked. Question Al Figure 1 shows an image in jpeg format, with the file properties listed as follows. Width Height Horizontal resolution Vertical resolution Color depth File size File format Page 1 of 8 540 pixels 361 pixels 200 dpi 200 dpi 24-bit 51 KB JPEG Figure 1 (a) What is the total number of pixels in this image? Show your calculation. (1 mark) (b) What are the dimensions (width and height) of the image in terms of inches? Show your calculation. (2 marks) (c) The image has a color depth of 24-bit. What does it mean? (2 marks) (d) The file size of the image is 51 KB. Suggest TWO ways, with explanation, that can reduce the file size. (4 marks) a (e) Other than checking the file extension, explain how you could identify whether an image is bitmap graphic or vector graphic. (4 marks) (f) Explain whether it is suitable to use vector graphic format to save the image shown in Figure 1. (2 marks) Page 2 of 8